Four Bar Drive Link Simulator

ABSTRACT

This invention relates to a mechanical fixture which simulates a four bar link drive system for pedal driven scooters and bicycles and the resulting drive system. A four bar drive link system simulator has a frame assembly, a proximal hinge attachment bracket, a bottom bracket simulator, a pair of crank levers, a pair of coupling levers and a pair of pedal levers. The frame assembly has a plurality of guide rails, including at least a proximal hinge adjustment rail, and a frame rail. The proximal hinge attachment bracket is connected to the proximal hinge adjustment rail. The bottom bracket simulator is attached or otherwise connected to the frame simulator rail.

TECHNICAL FIELD

This invention relates to a mechanical fixture which simulates a fourbar link drive system for pedal driven scooters and bicycles. Moreparticularly the simulator allows a wide range of link dimensions to bequickly evaluated for pedal performance and provides an easy way to finda set of dimensional solutions for optimal pedal performance. Thesimulator replicates the pedal action and accurately permits theevaluation each of the four link dimensions.

BACKGROUND OF THE INVENTION

Pedal driven bicycles have been well known in the art of man poweredvehicles. The most common pedal system uses a chain driven pair ofsprockets to which pedals are attached to the front drive sprocket whilea chain is attached to the front drive sprocket and the rear wheelsprocket propelling the rear wheel to provide movement. This system hasthe pair of pedals positioned 180 degrees relative to the other, so incombination, they rotate 360 degrees about the axis of rotation of thedrive sprocket; with the rider exerting maximum force on each downwardmotion on each pedal. This is a most simple and efficient way to move atwo wheeled bicycle.

A more complicated, but arguably superior drive system for a bicycle orscooter has been developed utilizing a four bar link drive mechanism.The drive mechanism employs a drive sprocket attached to a bottombracket fixed onto a bicycle or scooter frame, a crank link attached tothe drive sprocket or the axle of the drive sprocket and rotationallyfixed to the rotation of the drive sprocket, a coupling link attached atone end to the crank link and at an opposite end to a foot pedal, thefoot pedals being pivotally attached at one end to the crank link and atan opposite end, the foot pedal is pivotally attached at an end, calledthe proximal hinge location of the vehicle frame forming a four barlinkage assembly wherein the distances between axis of rotations at thevarious attachment locations define the movement. The distance betweenaxis of the pedal proximal hinge location attachment to the frame andthe axis of the drive sprocket forms a virtual frame link F. Thedistance between the axis of the proximal hinge location of the pedal tothe axis of the coupling link to pedal attachment defines a dimension P,the distance between pair of axis of the coupling link defines adimension C₂ and the dimension between the pair of axis of the cranklink defines a dimension C₁. The combination of dimensions F, P, C₁ andC₂ define the four bar linkage and are critical to the performance ofthe foot pedals and the vehicle. This drive mechanism as describedprovides a reciprocating pedal action wherein the rider can exertdownward pressure on each downward pedal stroke to propel the vehicle.The foot pedals are set so when one pedal is at the bottom of itsstroke, the other pedal is approximately at its maximum stroke relativeto the other so that the rider can provide alternating propulsionstrokes with each leg.

This drive mechanism is described in greater detail in U.S. patentapplication Ser. No. 12/554,366 filed on Sep. 4, 2009 entitled“Pedal-Drive System for Manually Propelling Multi Wheeled Cycles” andSer. No. 12/848,567 filed on Aug. 2, 2010 entitled “Improved Scooter andPedal Drive Assembly; the entirety of each application beingincorporated herein by reference.

The present invention does not claim this four bar linkage drive system,but rather teaches and discloses a unique simulator device capable ofproviding optimal solutions to the physical location and dimensions ofthe four bar linkage system.

During the development of a reciprocating pedal drive system it wasdiscovered that the positioning of the components on a vehicle framesuch as a scooter or bicycle were critical. The dimensions and relativelocations of F, P, C₁ and C₂ affected how the foot pedals moved. Minoradjustments of one element affected the entire pedal performance.Selection of these dimensions was such that minor variations inmanufacturing tolerances during assembly could result in poor pedalaction.

These problems were not simply poor pedal operation, but included alinkage lock up preventing pedal movement or even pedal reversal causingthe linkages to change or reverse direction. The present inventiondescribes a device to enable quick and reliable establishment of thesecritical dimensions.

SUMMARY OF THE INVENTION

A four bar drive link system simulator has a frame assembly, a proximalhinge attachment bracket, a bottom bracket simulator, a pair of cranklevers, a pair of coupling levers and a pair of pedal simulator levers.The frame assembly has a plurality of guide rails, including at least aproximal hinge adjustment rail, and a frame simulator rail. The proximalhinge attachment bracket is connected to the proximal hinge adjustmentrail. The bottom bracket simulator is attached or otherwise connected tothe frame simulator rail. The pair of crank levers is each attached at afirst end to an axle having its axis of rotation in the bottom bracketassembly, one crank lever being on one side of the bottom bracketassembly, the other on the opposite side. The pair of coupling levers iseach attached to an opposite second end of the crank lever. The pair ofpedal simulator levers is each pivotally attached to an end of thecoupling lever and to an axis of rotation of the proximal hingeattachment bracket. The relative dimensions between the axis of rotationof proximal hinge and axis of rotation of the bottom bracket areadjustable by movement along the proximal hinge guide rail or the framesimulator guide rail or a combination of both.

The pair of pedal simulator levers each has an adjustable couplingattachment bracket. Movement of the adjustment bracket changes thedimensional distance between axis of rotation of the proximal hingebracket and the pivotal attachment end of the coupling lever. The pedalsimulator levers also each have a pedal stroke lever angularlyadjustable to change the bend angle of the pedal simulator levers. Thefour bar drive link system simulator may have a second bottom bracketsimulator slidably mounted onto the frame simulator guide rail. Thesecond bottom bracket simulator has an axle to which a pair of sprocketscan be attached. The frame assembly further may have a rear lateralguide rail onto which an adjustable rear wheel mounting assembly forattaching a rear wheel sprocket and axle assembly is affixed whereinchain alignment of the vehicle can be simulated and adjusted by lateralmovement. In a preferred embodiment, the crank lever has a moveablyadjustable coupling attachment to change the crank lever length betweenthe axis of rotation of the bottom bracket and the coupling leverattachment. The crank lever may be a spider lever for attachment onto adrive sprocket and the spider lever has the adjustable couplingattachment. Similarly, the coupling levers may have movably adjustablepedal attachments for changing the coupling lever length between thecrank lever attachment and the pedal simulator attachment.

The invention can include A pedal assembly for us with a four bar drivesystem comprising: a front portion block; a front portion adjustment rodslidably attached to said front portion block; and, a rear portion blockattached to said front portion adjustment rod so that the distancebetween the front portion block and the rear portion block can bemodified. The invention can include a coupling lever having a frontcoupling block rotatably attached to said front portion rear block;coupling rods slidably attached to said front coupling block; and, arear coupling block attached to said coupling rods so that the distancebetween the front coupling block and the rear coupling block can bemodified. The invention can include a crank lever having a front crankblock rotatable attached to said rear coupling block; a crank rodslidably attached to said front crank block; and, a rear crank blockattached to said crank rod so that the distance between the front crankblock and the rear crank block can be modified.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the present invention four bar drivelink simulator.

FIG. 1A is the perspective view of the four bar drive link simulator ofFIG. 1 with one pedal simulator removed to allow viewing of the cranklever and coupling lever.

FIG. 2 is a side plan view of the four bar drive link simulator madeaccording to the present invention.

FIG. 3 is a top view of the four bar drive link simulator made accordingto the present invention.

FIGS. 4 and 4A are exploded views of the four bar drive link simulatorassembly of FIG. 1.

FIG. 5 is an end view of the four bar drive link simulator.

FIGS. 6, 6A, 7 and 7A are an exemplary scooter with a four bar drivelink mechanism. FIG. 6 being a perspective view, FIG. 6A being a topview and FIG. 7 being a side view.

FIG. 8 is a perspective view of an adjustable pedal portion of a pedalsimulator made according to the present invention.

FIG. 8A is an exploded view of the adjustable pedal portion of FIG. 8.

FIG. 9 is a perspective view of an angular adjustable pedal leverportion of the pedal simulator made according to the present invention.

FIG. 9A is an exploded view of the angular adjustable pedal leverportion of FIG. 9.

FIG. 10 is an exploded perspective view of a crank lever made in aspider construction for direct attachment onto a drive sprocket with anadjustable slide for changing the dimensional length of the cranklength.

FIGS. 10A and 10B are opposite perspective views of the crank lever ofFIG. 10.

FIG. 11 is a perspective exploded view of a coupling lever having anadjustable slide portion for changing the dimensional length of thecoupling lever.

FIGS. 11A and 11B are opposite assembled views of the adjustablecoupling length of FIG. 11.

FIG. 12 is a top view of the simulator showing a rear wheel andsprockets and chains for chain alignment.

FIG. 13 is a perspective of one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present device, as illustrated in FIGS. 1 through 5, is directed toa four bar drive link simulator 10 which provides a fast, predictableway to establish optimum dimensions for a four bar drive link mechanismused on bicycles or scooters.

To better appreciate the function of the simulator 10, it is best torefer to an exemplary scooter 100 as shown in FIGS. 6, 6A and 7 tounderstand how the four bark drive link mechanism works in an actualvehicle.

With reference to FIGS. 6, 6A and 7, an improved pedal drive scooter 100is illustrated. The scooter 100, as shown, has a frame 110 including ahandlebar assembly 120 including the handle bar grips, a shaft 120Awhich extends through and is secured to a hub on the frame 110 of thescooter 100. The shaft extends below the hub to a forked portion whichis secured to an axle on the front wheel of the scooter 100. Thesteering assembly 120 allows the front wheel to be maneuvered forsteering and turning. The frame structure 110 extends from the hubrearwardly to a yoke which connects the rear wheel to the frame 110. Asillustrated, the frame 110 has a step down portion which is connected tothe hub and extends substantially downwardly to the bottom of a frame110 to which a main frame support bar 130 is attached. As shown, at theattachment of the main support bar 130 to the step down portion of theframe 110, a supporting gusset is welded providing additional strengthand stiffness at this location. Welded onto the main support bar 130 isa bottom bracket 160, this bottom bracket 160 provides a location for adrive mechanism 200 assembly to be mounted. The drive mechanism 200, asillustrated, includes a drive sprocket 600. Attached to the drivesprocket 600 is a drive chain which extends rearwardly back to the rearwheel sprocket. The sprocket is attached to the axle of the rear wheeland as the device is operated, turns the rear wheel providing forwardpropulsion.

Attached to each side of the frame 110, as illustrated in FIGS. 6, 6Aand 7, are a pair of foot pedals 220R and 220L. The foot pedals 220R and220L are attached to the frame 110 at location 50. This location 50 willbe referred to hereafter as the proximal hinge attachment location 50.The foot pedal 220L is a mirror image of the foot pedal 220R. These footpedals operate in reciprocating motion, up and down and are connected tothe drive mechanism 200 to provide forward propulsion. As the pedals aremoved in an up and down direction, the sprocket is rotated moving thechain which in turn moves the rear sprocket, and propels the rear wheel.

The proximal hinge location 50 extends to the intersection at or nearthe bend to the reinforced pedal attachment location 24 and extends adistance P, as illustrated. A virtual frame link is created between theproximal hinge location 50 of the frame 110 and the axis if rotation orcenter of the axle of the drive mechanism 200. This virtual frame linkdistance is illustrated in FIG. 7 as a dimension F. The two ends of theframe link are fixed in location and do not move except rotationallyrelative to the other. As the pedals 220L and 220R reciprocate up anddown, the coupling links 320 and the crank links 310L and 31 OR rotatealong with the sprocket 600. As illustrated, the coupling link 320extends from the pedal attachment location 24 back to a pin locationconnecting the coupling links 320 and the crank link 310L or 310R. Thisdimension is identified as C₂. Extending from the coupling link pinlocation and crank attachment, a distance of C₁ is illustrated extendingback to the drive axle and the sprocket 600. It is important to notethat the coupling link dimension C₂ is substantially larger than thecrank link dimension C₁, as illustrated. Preferably, the coupling linkdimension C₂ must be greater than the dimension C₁, furthermore, it isnoted that the proximal hinge location 50 attaching the foot pedal 220Lor 220R to the frame 110 extends vertically, preferably, above the driveaxle location. This vertical distance is indicated as Y in thisexemplary scooter design.

An important aspect of the dimensional positioning of the four barlinkage is proper rotation of the coupling link 320 and the crank lever310L or 310R. If the locations are not accurately located, the drivemechanism 200 can lock up wherein a lock up phenomena is understood tooccur at a top dead center location causing the links to bind, stoppingthe pedals from moving. A worse problem can occur wherein the linkagescan actually reverse rotational direction. In this case a pedal canabruptly slam down as the links rotate opposite to their normal ordesired movement. The present invention avoids these issues entirely bya proper selection of four bar link dimensions F, P, C₁ and C₂. Theseproblems, while understood to exist, were not fully appreciated.Computer software which models and predicts dimensions for four barlinkage systems relies on the axle in the bottom bracket to be thedriving location and as such the predicted optimal locations for such adevice acted perfectly when one rotated at the axle by hand, but whenthe drive propulsion was moved to the location 24, as in the actualscooter device, these software optimum solutions would not operateproperly. It was determined that each of the link dimensions and therelationship of C₂ being greater than C₁ and the proximal hinge locationwere all critical. This meant finding optimal dimensions was notpredictable using standard software generated solutions. The performanceof the present invention was greatly enhanced by the selection of thelink dimensions and attachment locations on the frame 110. The solutionfound in the exemplary scooter allows for the dimensions to deviateslightly within normal manufacturing tolerance without the lock up orreversal issues that previously existed in the drive mechanism design.

The critical problem of using this type of four bar drive link mechanismin scooters and bicycles was finding a quick, reliable way to design anddevelop new frames, pedals and drive components that had predictableperformance, acceptable manufacturing tolerances and avoiding the lockup or reverse rotational issues that simply were not easily predictableusing computer modeling.

What was needed was a device that not only was reliable, but one inwhich the design engineers could confidently mimic real worldperformance of virtually unlimited range of dimensional variation tofind optimal performance characteristics.

The present invention simulator shown in FIGS. 1-5 mimics theperformance of the vehicle drive mechanism 200 so that prior toexpending the tooling cost on a frame and drive assembly, the designersknow with high confidence the performance of the drive mechanism.

With reference to FIGS. 1-5, the four bar drive link simulator 10 of thepresent invention is illustrated. As shown, the simulator 10 has a frameassembly 11, a proximal hinge attachment bracket 20, a bottom bracketsimulator 40, a pair of crank levers 31L, 31R, a pair of coupling levers32 and a pair of pedal simulator levers 22L, 22R. The frame assembly 11has a plurality of guide rails including at least a proximal hingeadjustment rail 22 and a frame simulator rail 13. The proximal hingeadjustment rail 22, as shown on the simulator 10, extends generallyvertically upwardly having guide slots 21 as illustrated. Attached tothe proximal hinge adjustment rail 22 is a proximal hinge attachmentbracket 20, this attachment bracket 20 is slidable on the guide rail 22such that it can move up and down vertically as illustrated. Thisvertical movement enables the proximal hinge location 50 which will be alocation on the frame of the vehicle to be properly duplicated orsimulated. The proximal hinge attachment bracket 20 can be snuglysecured at any position along the vertical guide rail 22 by using athreaded fastener locking the bracket 20 into a fixed position if sodesired. Extending longitudinally along the simulator 10 is the framesimulator rail 13, similarly having a plurality of guide slots 14 ontowhich a bottom bracket simulator 40 is attached or otherwise connected.As shown, the bottom bracket simulator 40 can be moved along the framesimulator rail 13 such that it moves forward or aft simulating thelocation of a bottom bracket that would be welded or otherwise attachedto a frame of a vehicle. These two movable brackets 20 and 40 of thesimulator 10 establish attachment locations for the crank levers,coupling levers and pedals as illustrated. The proximal hinge location50 has an axle 23 sticking outwardly such that a pedal simulator 22L or22R can be slipped onto the axle of the proximal hinge bracket 20 to fixthe location of the pedals 22L or 22R relative to the proximal hingelocation 50. This pedal simulator 22L or 22R as shown can movevertically up and down relative to the simulator 10. As shown in FIG.1A, one pedal simulator 22L is removed from the axle 23 of the proximalhinge bracket 20 clearly exposing the axle 23 as well as a pair of cranklevers 31L, 31R and coupling levers 32 which are attached to the bottombracket simulator 40. The crank lever 31R and the coupling lever 32 areconnected to the pedal simulator 22R as illustrated in FIG. 1A such thatthey provide an attachment location onto the pedals and enable the drivemechanism 200 to then simulate the movement of the drive mechanism 200by reciprocating motion of the pedal levers 25. To accomplish this onesimply grasps the ends of the pedal levers 25 and moves them up and downrepeating that action to simulate the performance of the drive mechanism200.

The exploded view of the simulator 10 shown in FIG. 4, illustrates thevarious locations of the components as previously described. As shown,at the forward and rear end of the simulator 10 a pair of laterallyextending guide rails 72, 74 are attached to the frame simulator rail 13and proximal hinge guide rail 22 on the forward part of the frameassembly 11. On the rear part of the frame assembly 11, as illustrated,a second vertical guide rail 82 is shown along with the lateral guiderail 74 to which a pair of rear wheel mounting brackets 90, 92 areshown, the rear wheel mounting brackets 90, 92 as illustrated, enable arear wheel or rear wheel sprocket and hub to be attached such that achain can be attached to either a sprocket attached on an axle 44 of thesecond bottom bracket 41 as illustrated or alternatively directly to asprocket attached on the first bottom bracket 40. The sprockets notbeing illustrated in FIG. 4, however, it being understood that they canbe attached directly onto the axles 42, 44 of the bottom bracketsimulators 40, 41.

Referring to FIG. 4A, post 150R and 150L are shown attached to the pedalassembly and received by openings 152R and 152L the respective couplinglevers 32. By attaching the post to the pedal assembly, rather than thecoupling lever, the tolerances needed for proper operation are lessened.A bearing can be placed in the coupling opening in one embodiment.

As shown in FIG. 12, a rear wheel hub assembly 99 can then be attachedto the attachment brackets 90, 92 for a rear wheel such that chainalignment can be predicted and established using the simulator 10. Thisis a second feature of the simulator that enables a direct analysis ofchain alignment to be predicted and made utilizing the simulator 10 asshown.

For better understanding of the adjustment capability of the simulator10, it is understood that the bottom bracket simulator 40 attached tothe frame simulator rail 13 enables a movement fore and aft along thesimulator 10 whereas the proximal hinge bracket 20 enables a verticalmovement up and down the proximal hinge guide rail 22 allowing foradjustment of the virtual frame link dimension F. As the virtual framedimension F is adjusted, correspondingly the pedal link dimension P fromthe proximal hinge location 50 to the coupling attachment location 24 atthe foot pedals 22L, 22R are correspondingly moved.

In order to accomplish this movement, the pedal simulator 22L and 22R asshown has a forward portion 30L, 30R which is shown slightly bent thatattaches to the proximal hinge axle 23 at the forward hub end 35. At therear end 37 as illustrated in FIG. 8A, has a slot 34 into which acylindrical sleeve 38 fits. A screw attachment thread hole 39 has a bolt65 attached. A thumb lock down nut 66 secures a movable bracket 36 thatis attached to the sleeve 38 at the holes 36A, 36B enables this locationto be moved fore and aft. This allows the link dimension P to beadjusted by simple turning of the threaded fastener or bolt 65 whichmoves the bracket 36 and correspondingly enables the sleeve 82 in theslot 34 to be moved either forward or aft as so desired. The bolt 65passes through the hole 36C in the bracket 36 and the bracket is fixedby the thumb nut 66.

With reference to FIGS. 9 and 9A, a pedal lever assembly 25 is shown,the pedal lever assembly 25 includes a pair of threaded fasteners 27 towhich nuts 26 are applied that extend through a hole 28 locating a pairof angular orientation brackets 25A to be connected to the lever 25B asshown, the brackets 25A have holes 28A at one end that allow thethreaded fastener 27 to slip through a hole 29B in the lever 25B and beconnected by a nut 26 at the other end. At the arcuate end of thebracket 25A is an arcuate slot 29A, the fastener can be slipped throughthe slot 29A and into a second hole 29B in the lever arm 25B and a nut26 attached to it. Adjustment of the angle can be achieved by simplyloosening the second fastener 27 such that an angular movement in the29A of the bracket 25A can occur.

This pedal lever assembly 25 of FIG. 9 is then welded or otherwiseattached to the portion 37 of the bracket 30L, or 30R shown in FIG. 8and as illustrated in FIG. 4 in the exploded view. As illustrated, thisenables the pedal lever simulator 22L, 22R to be adjusted not onlydimensionally fore and aft to change the link dimension P by tighteningor loosening the bolt 65, but also angularly to change the angle of thepedal lever assembly 25 such that vertical movement up and down can beadjusted. In doing so, it must be noted that as illustrated, thesimulator 10 allows the pedal on one side to be at a substantiallyhorizontal position while on the opposite side the pedal is at themaximum angled position. This is how the pedals operate. The bottom ofthe stroke which is generally set at a horizontal position and theopposite pedal is at its maximum or peak position of the strokereciprocating movement alternates these positions and is what drives thedrive mechanism in a reciprocating fashion so that the pedals cancontinuously move. If so desired, at the bottom of the stroke, the anglecould be extended slightly below horizontal.

The simulator 10 shown in FIGS. 1 and 4 had fixed coupling levers 32 andfixed crank levers 31L, 31R such that the dimensions are fixed C₂ and C₁respectively. In order to make additional adjustments with regard tothese features, and to find optimal coupling lever and crank leverdimensions, it was determined that an adjustment feature could also beprovided on a crank lever and a coupling lever. To achieve this,adjustment slots are provided in both of these components. This featureis as illustrated in FIGS. 10, 10A and 10B for an exemplary spider cranklever 31AL, the spider crank lever 31AL is a type of device thatattaches or bolts directly onto a drive sprocket of a vehicle at thefour spider arms 314. As shown in FIG. 10, this spider crank lever 31ALcan have a slide 311 that fits in the slot 312. This slide component 311is slidably moveable within the slot 312, but can be fixed at anylocation within the slot 312 by threaded fasteners 400 as illustrated.The fasteners 400 fit in slots 402 and fasten in the holes 315 in theslider 311. The opposite perspective views shown in FIGS. 10A and 10B,show the slide 311 moved to a most forward location wherein thedimension C₁ would be at a minimum on this device. To make an adjustmentincreasing the length, one would simply move the slider 311 aft and thedistance between the attachment and the axle 42 on the bottom bracketsimulator 40 and the coupling attachment opening 313 shown in the slider311 would move in such a direction enabling an increase in length of thedimension C₁.

As shown in FIGS. 11, 11A and 11B; a coupling lever 32A is illustratedhaving a similar slider 311 that can be inserted into a slot 312 in thecoupling lever 32A. This coupling lever 32A can then have the slider 311fastened using threaded fasteners 400 as illustrated. In this component,the coupling lever 32A can be designed so that adjustments can be madein the dimension C₂ between the pedal attachment location 24 and thecrank attachment location 313. This dimension C₂ can be adjustedincreasing or decreasing the length if so desired. As shown in FIGS. 11Aand 11B, the coupling lever 32A has the slider 311 at a minimumlocation; movement in an opposite direction in the slot 312 would allowthe dimension C₂ to be increased substantially. As such, a large numberof variations can occur within the adjustable crank levers 31AL, 31ARand coupling levers 32A. As these elements are placed on the simulator,not only can the dimensions P and F be adjusted along the guide rails22, 13, but also by providing a pedal lever simulator 22L, 22R with anadjustment feature, along with crank levers and coupling levers withslidable adjustment features, every dimension used in establishing afour bar link system can be adjusted. These adjustments can be madeeither singularly or in combination to create virtually any combinationof four bar drive link system dimensions desired within the range of thecomponents ability to be adjusted. This provides the designer withalmost an infinite range of selectable solutions for the drive mechanismused in such scooters and bicycles.

In using the simulator 10 as illustrated, the drive mechanism can beadjusted in a variety of ways. This drive mechanism dimensions, onceestablished at an optimum by repeated movement of the pedal simulatorlevers as illustrated, enable the designer to get a feel for the actualmovement that will be achieved in the finished scooter or bicycle.Instead of using feet to drive the pedal lever arms 25, it is desirableto use ones hands and to move these levers up and down simulating themotion of the feet, in doing so the operator gets a feel for the ease inmovement of the four bar link system and as such can make minoradjustments until the movement is felt to be optimal. Once the movementis optimally set, the engineer can simply take the measurements relativeto the axis of rotation of each of the attachment locations such thatthese dimensions are established. These dimensions; F, P, C₁ and C₂ areclearly established by the simulator.

When using the simulator device 10 the procedure for fixed linksoutlined below can be followed to establish the four bar drive linkdimensions. Step 1: Choose approximate angle of bend for pedals. Step 2:Choose approximate distance between bolts in pedal. Note: increasingdistance will decrease pedal stroke angle. In turn, decreasing distancewill increase pedal stroke angle. Step 3: Adjust height of proximalhinge and linear distance of bottom bracket until pedal is at an angleof zero degrees from horizontal when at bottom of stroke. Step 4:Continue to adjust linear distance of bottom bracket until drive systemrotates freely. Fine tuning is necessary to find the best location ofbottom bracket and to obtain tolerances for manufacturing. If pedalstroke angle is not as desired, adjust the distance between the bolts inthe pedal. Increase the distance to decrease the angle, in turn,decrease the distance to increase the angle. Repeat steps 3-4. Oncedesired angle is achieved, adjust the pedal bend angle to zero when atbottom of stroke.

When using the simulator device 10 the procedure for adjustable linksoutlined below can be followed to establish the four bar drive linkdimensions. Step 1: Choose approximate angle of bend for pedals. Step 2:Choose approximate distance between bolts in pedal. Note: increasingdistance will decrease pedal stroke angle. In turn, decreasing distancewill increase pedal stroke angle. Step 3: Choose approximate dimensionsfor links. Note: Linear length of Crank link should be greater than thatof the Coupler link. Note 2: Increasing the length of the Crank linkincreases tolerances, decreasing the length decreases tolerances. Thecombined length of the longest length and the shortest length must notbe greater than the combined length of the remaining two links. Step 4:Adjust height of proximal hinge and linear distance of bottom bracketuntil pedal is at an angle of zero degrees from horizontal when atbottom of stroke. Step 5: Continue to adjust linear distance of bottombracket until drive system rotates freely. Fine tuning is necessary tofind the best location of bottom bracket and to obtain tolerances formanufacturing. If pedal stroke angle is not as desired, adjust thedistance between the bolts in the pedal. Increase the distance todecrease the angle, in turn, decrease the distance to increase theangle. Repeat steps 3-4. Once desired angle is achieved, adjust thepedal bend angle to zero when at bottom of stroke. Once this has beenaccomplished, the designer can feel confident that the drive mechanismsimulation has provided him with a solution that will provide a good,reliable and predictable drive mechanism.

Once this is accomplished, the other aspect of this invention is to usethe rear portion of the simulator 10 to attach a wheel or hub 99 asillustrated and to attach sprockets 98 onto the either second bottombracket 41 or simply the first bottom bracket 40 and to provide forchain alignment, as shown in FIG. 12. Chain alignment is criticalbecause in a two chain system, the drive sprocket 98A is on one sideextending back to a smaller sprocket 97 on the second bottom bracket 41which is also connected on the opposite side to a larger sprocket 98Bwhich is then connected to a rear wheel hub sprocket 98C to put drivepropulsion to the rear wheel. This creates potential for misalignment ofthe chains 95, 96; accordingly it is important that the simulator 10provides for chain alignment variations and the engineer can then takemeasurements off of the simulator 10 to establish proper dimensions onthe frame and locations that the bottom brackets must be welded to theframe in order to achieve proper chain alignment and also to provideproper attachment locations for the rear wheel assembly onto the frameitself. These features are all achieved with the present invention asillustrated and described above, while variations and minor adjustmentscan be made, it is understood that this simulator will provide apredictable and reliable way of establishing a four bar drive linksystem for a scooter or bicycle having reciprocating pedals as describedherein.

Referring to FIG. 4A, the invention is shown in more detail. In thepast, and as shown in U.S. Pat. No. 8,128,111, a post is attached to thecoupling arm. The post is received in a pedal opening defined in thepedal lever at the reinforced pedal attachment location 24. A bearingcan be inserted into the pedal opening allowing the post to more easilyrotate in the pedal opening. In this configuration, the precisionrequired in the dimensions of F, P, C₁ and C₂ is critical to properoperating. However, an advantage to the tight tolerances with thisconfiguration is that the rider experiences a motion with little “slack”or “sloppiness” as the various components interact.

In one embodiment, the tolerance necessary in to provide for a properlyfunctioning four bar drive link system can be lowered by attaching thepost to the pedal arm rather than the coupling lever. Referring to FIG.4A, pedal simulators 22R and 22L can include a right post 150R and aleft post 150L. The coupling levers 32 include a right post opening 152Rand a left post opening 152L for receiving the right and left postsrespectively. A coupling bearing can be inserted in to the post openingsto assist with the rotation of the posts with the post opening. In thisconfiguration, the dimensions of F, P, C₁ and C₂ need not has such acritical relationship so that variations in the alignment of the postand the post opening that occur in manufacturing are less likely toresult in an inoperable four bar drive system. Therefore, when thesimulator is used determine the proper dimensions for F, P, C₁ and C₂,the manufactured drive system itself can vary, especially C₂. Therefore,when the simulator is used to determine the proper C₂, the drive systemitself can have a different dimension C₂′. In one embodiment C₂′ iswithin ten percent (10%) of the dimensions of C₂.

Referring to FIG. 13, one embodiment of the invention is shown. Theframe assembly 11 include the proximal attachment hinge assembly 20moveably attached to the guide slot 21. The forward portions 30R and 30Lof the pedal simulator at rotatably attached at the proximal hinge point50. The forward portions include a front portion block 222R and 222L.Forward portion adjustment rods 224Ra, 224Rb, 224La and 224Lb areslidably attached to the front portion block. Rear portion blocks 226Rand 226L are attached to the forward portion adjustment rodsrespectively allowing the distant between the front portion block andthe rear portion block to be changed by sliding the front portion rodsin an out of the front portion blocks thereby changing the dimensions ofthe front portion. The forward portion adjustment rods can have a lockedposition so that they do not slide about the front portion block and anunlocked position allowing the rods to slide within the front portionblock.

The couplings 32 can each include a front coupling block 228R and 228Lrotatably attached to the rear portion blocks respectively. Couplingrods 230Ra, 230Rb, 230La and 230Lb are can be slidably connected to thefront coupling block. Rear coupling blocks 232R and 232L are attached tothe coupling rods. The coupling rods can have a locked position whereinthey cannot slide about the front coupling block and an unlockedposition where they can slide about the front coupling block changingthe distance between the distance between the front coupling block andthe rear coupling block.

The crank arms 31R and 31L can each include a front crank block shown as234R and 234L that is rotatable attached to the rear coupling block.Crank rods 236Ra and 236Rb can be slidably attached to the front crankblocks. Rear crank blocks 238R and 238L can be attached to the crankrods so that when the crank rod slide about the front crank block, thedistance between the front crank blocks and the rear crank blocks ischanged. The crank rods can have a locked and unlock position where inthe unlocked position the crank rods can slide about the front crankclocks. The rear crank block can be rotatably attached to a axle 42.

The rear forward portion block can include opening 240 a through 240 dfor receiving the pedal lever 25. In one embodiment, the pedal leverangle relative to the front portion is changed based upon the openingreceiving the pedal lever. Each opening is positing at a differentlocation within the forward portion rear block which in turn effects theleverage experienced by the rider and the motion of the drive system. Inone embodiment, a post is orthogonally attached to the forward portionrear block and is receiving in to the front coupling block. By usingthis configuration, the tolerances needed to provide for properoperation are relaxed. Further, the pedal assembly can to determineperformance of a straight pedal lever as well as an angled pedal lever.

In operation, when the link dimensions within the pedal assembly, arevaried, the pressure on the bearing that can be include in eachrotational attachment, are calculated to produce acceptable bearing lifepredictions. The bearing must have nearly concentric inside ad outsidemovements for substantial performance life and acceptable noise levels.

As illustrated, each of the attachment locations where pivotal motionoccurs, it may be desirable to provide bushings or bearings to smoothrotation, assuming the vehicle being simulated employs these components.Therefore, the use of such bushings and bearings is used if they arealso used on the vehicle. Furthermore, the axles 42, 44 of the bottombrackets can be square or round splined ends, but similarly should matchthe vehicle being simulated.

Variations in the present invention are possible in light of thedescription of it provided herein. While certain representativeembodiments and details have been shown for the purpose of illustratingthe subject invention, it will be apparent to those skilled in this artthat various changes and modifications can be made therein withoutdeparting from the scope of the subject invention. It is, therefore, tobe understood that changes can be made in the particular embodimentsdescribed which will be within the full intended scope of the inventionas defined by the following appended claims.

What is claimed is:
 1. A four bar drive link system comprising: a frameassembly, the frame assembly having a plurality of guide rails,including at least a proximal hinge adjustment rail, and a framesimulator rail; a proximal hinge attachment bracket connected to theproximal hinge adjustment rail; a bottom bracket simulator attached orotherwise connected to the frame simulator rail; a pair of crank levers,each being attached at a first end to an axle having an axis of rotationin the bottom bracket assembly; a pair of coupling levers each attachedto an opposite second end of the crank lever wherein each coupling leverincludes a post opening; a pair of pedal levers each having a postwherein each post of each pedal lever is pivotally attached to itsrespective post opening and to an axle having an axis of rotation in theproximal hinge attachment bracket; and wherein the relative dimensionsbetween the axis of rotation of proximal hinge and axis of rotation ofthe bottom bracket are adjustable by movement along the proximal hingeguide rail or the frame simulator guide rail or a combination of both.2. The four bar drive link system of claim 1 wherein the pair of pedallevers each has an adjustable coupling attachment bracket, movement ofthe adjustment bracket changes the dimensional distance between axis ofrotation of the proximal hinge and the pivotal attachment end of thecoupling lever.
 3. The four bar drive link system of claim 1 wherein thepedal levers each have a pedal lever angularly adjustable to change thepedal bend angle.
 4. The four bar drive link system of claim 2 furthercomprising: a second bottom bracket simulator slidably mounted onto theframe simulator guide rail, the second bottom bracket simulator havingan axle to which a pair of sprockets can be attached.
 5. The four bardrive link system of claim 4 wherein the frame assembly furthercomprises a rear lateral guide rail onto which an adjustable rear wheelmounting assembly for attaching a rear wheel sprocket and axle assemblyis affixed wherein chain alignment of the vehicle can be simulated andadjusted by lateral movement.
 6. The four bar drive link system of claim1 wherein the crank lever has a moveably adjustable coupling attachmentto change the crank lever length between the axis of rotation of thebottom bracket and the coupling lever attachment.
 7. The four bar drivelink system of claim 6 wherein the crank lever is a spider lever forattachment onto a drive sprocket and the spider lever has the adjustablecoupling attachment.
 8. The four bar drive link system of claim 1wherein the coupling lever has a movably adjustable pedal attachment forchanging the coupling lever length between the crank lever attachmentand the pedal attachment.
 9. A pedal lever assembly for use with a fourbar drive link system comprising: a forward portion included in saidpedal assembly rotatably attached to a frame; a post attached to saidpedal assembly for being received in a post opening defined in acoupling lever so that said pedal assembly is pivotally attached to saidcoupling lever wherein said post is orthogonal in relation to the planeof movement of the pedal assembly; a crank lever rotatably attached tosaid coupling lever; and, a drive sprocket attached to said crank lever.10. The pedal lever assembly of claim 9 including a moveably adjustablecoupling attachment carried by said crank lever for adjusting theposition of the post opening along the length of the crank lever. 11.The pedal lever assembly of claim 9 wherein said crank lever is a spiderlever for attachment onto said drive sprocket and the spider lever hassaid adjustable coupling attachment.
 12. The pedal lever assembly ofclaim 9 wherein said post is attached to a movably adjustable pedalattachment for changing position of the post along the pedal lever. 13.The coupling lever of claim 9 wherein said pedal lever has a pedal leverangularly adjustable to change the pedal bend angle.
 14. A pedalassembly for us with a four bar drive system comprising: a front portionblock; a front portion adjustment rod slidably attached to said frontportion block; and, a rear portion block attached to said front portionadjustment rod so that the distance between the front portion block andthe rear portion block can be modified.
 15. The pedal assembly of claim14 including: a coupling lever having a front coupling block rotatablyattached to said front portion rear block; coupling rods slidablyattached to said front coupling block; and, a rear coupling blockattached to said coupling rods so that the distance between the frontcoupling block and the rear coupling block can be modified.
 16. Thepedal assembly of claim 15 including: a crank lever having a front crankblock rotatable attached to said rear coupling block; a crank rodslidably attached to said front crank block; and, a rear crank blockattached to said crank rod so that the distance between the front crankblock and the rear crank block can be modified.
 17. The pedal assemblyof claim 14 including an opening in said forward portion rear block forreceiving a pedal lever.
 18. The pedal assembly of claim 14 including aplurality of opening defined in said forward portion rear block eachhaving different angles of incident so that when a pedal lever isinserted in said opening, the pedal angle is unique to each opening. 19.The pedal assembly of claim 19 including a plurality of opening definedin said forward portion disposed along the forward portion rear block sothat when a pedal lever is inserted in said opening, the pedal angle isunique to each opening.
 20. The pedal assembly of claim 14 including apost orthogonally attached to said forward portion rear block.